You mean entirely distinct CQL statements issued by the same client “concurrently”?
If they’re submitted to the same coordinator then M2 will have a higher timestamp than M1, so if M2 applies first then M1 will be a no-op and should not generate any view update. If submitted to different coordinators with server-issued timestamps then unless timestamps clash, one of them will win, but it may not be M2. > On 19 Aug 2022, at 11:14, Claude Warren, Jr via dev > <dev@cassandra.apache.org> wrote: > > Perhaps my diagram was not clear. I am starting with mutations on the base > table. I assume they are not bundled together so from separate CQL > statements. > > On Fri, Aug 19, 2022 at 11:11 AM Claude Warren, Jr <claude.war...@aiven.io> > wrote: >> If each mutation comes from a separate CQL they would be separate, no? >> >> >> On Fri, Aug 19, 2022 at 10:17 AM Benedict <bened...@apache.org> wrote: >>> If M1 and M2 both operate over the same partition key they won’t be >>> separate mutations, they should be combined into a single mutation before >>> submission to SP.mutate >>> >>> > On 19 Aug 2022, at 10:05, Claude Warren, Jr via dev >>> > <dev@cassandra.apache.org> wrote: >>> > >>> > >>> > >>> > # Table definitions >>> > >>> > Table [ Primary key ] other data >>> > base [ A B C ] D E >>> > MV [ D C ] A B E >>> > >>> > >>> > # Initial data >>> > base -> MV >>> > [ a b c ] d e -> [d c] a b e >>> > [ a' b c ] d e -> [d c] a' b e >>> > >>> > >>> > ## Mutations -> expected outcome >>> > >>> > M1: base [ a b c ] d e' -> MV [ d c ] a b e' >>> > M2: base [ a b c ] d' e -> MV [ d' c ] a b e >>> > >>> > ## processing bug >>> > Assume lock can not be obtained during processing of M1. >>> > >>> > The mutation M1 sleeps to wait for lock. (Trunk Keyspace.java : 601 ) >>> > >>> > Assume M2 obtains the lock and executes. >>> > >>> > MV is now >>> > [ d' c ] a b e >>> > >>> > M1 then obtains the lock and executes >>> > >>> > MV is now >>> > [ d c ] a b e' >>> > [ d' c] a b e >>> > >>> > base is >>> > [ a b c ] d e' >>> > >>> > MV entry "[ d' c ] a b e" is orphaned >>> > >>> >
